The present work focused on neurophysiological and behavioral mechanisms related to healthy and pathological aging. The first study explored the behavioral and electrophysiological dynamics (N2pc and CDA) of multiple object processing in mild cognitive impairment and Alzheimer's disease (AD) patients to identify neurophysiological markers able to differentiate normal from pathological aging. Data suggested that CDA may be a useful neural signature to both distinguish between healthy and pathological aging and characterize the different stages along the AD continuum, possibly becoming a reliable candidate for an early diagnostic biomarker of AD pathology. The second study evaluated the possibility to apply a non-invasive neurorehabilitation protocol, by means of transcranial electrical stimulation (tES), to improve cognitive performance by increasing the level of arousal. Both the behavioral performance to a short term memory task and indexes of autonomic physiological activation (pupillary dilatation and skin conductance) were investigated in a group of healthy young subjects and in a group of healthy elderly subjects. In young, both behavioural and physiological responses were not modulated by tES application. In elderly, instead, real tES induced the report of a significant lower proportion of high salient stimuli, compared to the sham condition, suggesting a reduction of the memory span. The physiological indexes resulted unreliable in elderly participants and they could not be used to draw firm conclusions on the tES modulations of the level of arousal. These results showed that bursts of tES, applied during a short term memory task, differently modulated behavioural performance in young and elderly participants.
Il presente lavoro si è concentrato sui meccanismi neurofisiologici e comportamentali legati all'invecchiamento sano e patologico. Il primo studio ha esplorato le dinamiche comportamentali ed elettrofisiologiche (N2pc e CDA) del processamento di oggetti multipli in pazienti con decadimento cognitivo lieve ed in pazienti con malattia di Alzheimer (AD), al fine di identificare marcatori neurofisiologici per distinguere l’invecchiamento normale da quello patologico. I dati suggeriscono che la CDA può essere un marcatore neurale utile sia per distinguere tra invecchiamento sano e patologico che per caratterizzare le diverse fasi lungo il continuum della malattia di Alzheimer, diventando un biomarcatore per la diagnosi precoce di AD. Il secondo studio ha valutato la possibilità di applicare un protocollo di neuroriabilitazione non invasiva, mediante stimolazione elettrica transcranica (tES), per migliorare le prestazioni cognitive aumentando il livello di eccitazione. Sia le prestazioni comportamentali ad un compito di memoria a breve termine che gli indici di attivazione fisiologica autonomica (dilatazione pupillare e conduttanza cutanea) sono stati studiati in un gruppo di soggetti giovani sani e in un gruppo di soggetti anziani sani. Nei giovani, entrambe le risposte comportamentali e fisiologiche non sono state modulate dall’applicazione della tES. Negli anziani, invece, la stimolazione reale ha indotto la rievocazione di una proporzione significativamente più bassa di stimoli ad alta salienza, rispetto alla condizione sham, suggerendo una riduzione della capacità di memoria. Gli indici fisiologici risultano inaffidabile nei partecipanti anziani e non possono essere utilizzati per trarre conclusioni definitive sulle modulazioni indotte dalla tES sul livello di eccitazione. Questi risultati hanno mostrato che l’applicazione della tES, durante un compito di memoria a breve termine, modulano diversamente le prestazioni comportamentali nei partecipanti giovani ed in quelli anziani.
A MULTIMODAL APPROACH TO THE STUDY OF HEALTHY AND PATHOLOGICAL AGING
Panizza, Laura
2017
Abstract
The present work focused on neurophysiological and behavioral mechanisms related to healthy and pathological aging. The first study explored the behavioral and electrophysiological dynamics (N2pc and CDA) of multiple object processing in mild cognitive impairment and Alzheimer's disease (AD) patients to identify neurophysiological markers able to differentiate normal from pathological aging. Data suggested that CDA may be a useful neural signature to both distinguish between healthy and pathological aging and characterize the different stages along the AD continuum, possibly becoming a reliable candidate for an early diagnostic biomarker of AD pathology. The second study evaluated the possibility to apply a non-invasive neurorehabilitation protocol, by means of transcranial electrical stimulation (tES), to improve cognitive performance by increasing the level of arousal. Both the behavioral performance to a short term memory task and indexes of autonomic physiological activation (pupillary dilatation and skin conductance) were investigated in a group of healthy young subjects and in a group of healthy elderly subjects. In young, both behavioural and physiological responses were not modulated by tES application. In elderly, instead, real tES induced the report of a significant lower proportion of high salient stimuli, compared to the sham condition, suggesting a reduction of the memory span. The physiological indexes resulted unreliable in elderly participants and they could not be used to draw firm conclusions on the tES modulations of the level of arousal. These results showed that bursts of tES, applied during a short term memory task, differently modulated behavioural performance in young and elderly participants.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14242/159893
URN:NBN:IT:UNICATT-159893